1 2 static char help[] = "Tests sequential and parallel MatGetRow() and MatRestoreRow().\n"; 3 4 #include <petscmat.h> 5 6 int main(int argc, char **args) { 7 Mat C; 8 PetscInt i, j, m = 5, n = 5, Ii, J, nz, rstart, rend; 9 PetscMPIInt rank; 10 const PetscInt *idx; 11 PetscScalar v; 12 const PetscScalar *values; 13 14 PetscFunctionBeginUser; 15 PetscCall(PetscInitialize(&argc, &args, (char *)0, help)); 16 /* Create the matrix for the five point stencil, YET AGAIN */ 17 PetscCall(MatCreate(PETSC_COMM_WORLD, &C)); 18 PetscCall(MatSetSizes(C, PETSC_DECIDE, PETSC_DECIDE, m * n, m * n)); 19 PetscCall(MatSetFromOptions(C)); 20 PetscCall(MatSetUp(C)); 21 for (i = 0; i < m; i++) { 22 for (j = 0; j < n; j++) { 23 v = -1.0; 24 Ii = j + n * i; 25 if (i > 0) { 26 J = Ii - n; 27 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES)); 28 } 29 if (i < m - 1) { 30 J = Ii + n; 31 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES)); 32 } 33 if (j > 0) { 34 J = Ii - 1; 35 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES)); 36 } 37 if (j < n - 1) { 38 J = Ii + 1; 39 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES)); 40 } 41 v = 4.0; 42 PetscCall(MatSetValues(C, 1, &Ii, 1, &Ii, &v, INSERT_VALUES)); 43 } 44 } 45 PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY)); 46 PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY)); 47 PetscCall(MatView(C, PETSC_VIEWER_STDOUT_WORLD)); 48 49 PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank)); 50 PetscCall(MatGetOwnershipRange(C, &rstart, &rend)); 51 for (i = rstart; i < rend; i++) { 52 PetscCall(MatGetRow(C, i, &nz, &idx, &values)); 53 if (rank == 0) { 54 for (j = 0; j < nz; j++) PetscCall(PetscPrintf(PETSC_COMM_SELF, "%" PetscInt_FMT " %g ", idx[j], (double)PetscRealPart(values[j]))); 55 PetscCall(PetscPrintf(PETSC_COMM_SELF, "\n")); 56 } 57 PetscCall(MatRestoreRow(C, i, &nz, &idx, &values)); 58 } 59 60 PetscCall(MatDestroy(&C)); 61 PetscCall(PetscFinalize()); 62 return 0; 63 } 64 65 /*TEST 66 67 test: 68 69 TEST*/ 70